Cancer Risk After Pernicious Anemia in the US Elderly Population

• Published in: Clinical gastroenterology and hepatology Vol. 13; no. 13; pp. 2282 - 2289.e4
• Main Authors: Murphy, Gwen, Dawsey, Sanford M, Engels, Eric A, Ricker, Winnie, Parsons, Ruth, Etemadi, Arash, Lin, Shih-Wen, Abnet, Christian C, Freedman, Neal D
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-12-2015
• Subjects: Acid Secretion; Adenocarcinoma - epidemiology; Aged; Aged, 80 and over; Anemia, Pernicious - complications; Carcinoid Tumor - epidemiology; Case-Control Studies; Chronic Atrophic Autoimmune Gastritis; Female; Gastroenterology and Hepatology; Humans; Male; Parietal Cells; Risk Assessment; Stomach Cancer; Stomach Neoplasms - epidemiology; United States - epidemiology; United States; Stomach Cancer; OR; Parietal Cells; CI; SEER; confidence interval; Surveillance, Epidemiology, and End Results; odds ratio; Chronic Atrophic Autoimmune Gastritis; Acid Secretion
• ISSN: 1542-3565; 1542-7714
• DOI: 10.1016/j.cgh.2015.05.040

Background & Aims Pernicious anemia, a result of autoimmune gastritis, is the most common cause of vitamin B12 deficiency, affecting 2% to 5% of the elderly population. Treatment with vitamin B12 cures the anemia, but not the gastritis. Findings from small studies have indicated that patients with pernicious anemia could have an increased risk of cancer. Methods We performed a population-based, case–control study of individuals in the Surveillance, Epidemiology, and End Results–Medicare database, comparing 1,138,390 cancer cases (age, 66–99 y) with 100,000 matched individuals without cancer (controls). Individuals with pernicious anemia were identified based on their medical claims within the year before selection for the study. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression, and models were adjusted for sex, age, and calendar year of diagnosis and selection. Results Compared with controls, we found individuals with pernicious anemia to be at increased risk for noncardia gastric adenocarcinoma (OR, 2.18; 95% CI, 1.94–2.45) and gastric carcinoid tumors (OR, 11.43; 95% CI, 8.90–14.69). In addition, people with pernicious anemia have an increased risk of developing tonsilar cancer (OR, 2.00; 95% CI, 1.40–2.85), hypopharyngeal cancer (OR, 1.92; 95% CI, 1.35–2.73), esophageal squamous cell carcinoma (OR, 2.12; 95% CI, 1.76–2.55), small intestinal cancer (OR, 1.63; 95% CI, 1.32–2.02), liver cancer (OR, 1.49; 95% CI, 1.28– 1.73), myeloma (OR, 1.55; 95% CI, 1.37–1.75), acute myeloid leukemia (OR, 1.68; 95% CI, 1.46–1.93), and myelodysplastic syndrome (OR, 2.87; 95% CI, 2.53–3.26). People with pernicious anemia have a lower risk of rectal cancer than the general population (OR, 0.82; 95% CI, 0.74– 0.92). Conclusions In a population-based, case–control study of individuals in the Surveillance, Epidemiology, and End Results–Medicare database, we found individuals with pernicious anemia to have significantly increased risks of gastric carcinoid tumors, adenocarcinomas, and other cancers located throughout the body.